Vehicle Detection Sensors

Technologies

Identifying the right technology for your vehicle detection application can be challenging, and many factors must be taken into consideration, including task, size of target, sensing range, sensor mounting, and whether the application is primarily indoor or outdoor.

Wireless Magnetometer

A magnetometer works by using a passive sensing technology to detect large ferrous objects (for example, a truck, automobile, or rail car) by measuring the change in the ambient magnetic field. When a vehicle alters that magnetic field, the sensor detects those changes. The range of the magnetometer will depend on the target.

Wireless Ultrasonic Sensor

A wireless ultrasonic sensor is often an ideal solution for indoor or covered parking applications. Using sound waves to detect objects, an ultrasonic sensor can be mounted directly onto the ceiling of a parking garage to identify the presence of a vehicle in the parking space below. The sensor is taught a distinct point within its sensing range (e.g. the ground) and will detect any object regardless of shape, size or reflective angle that crosses between the sensor face and the taught point.

Wireless magnetometer detects vehicles near an automated gate

Radar Sensor

Radar sensors are ideal for long-range outdoor applications. Unlike photoelectric or ultrasonic sensors, radar sensors are not affected by conditions such as wind, rain, fog, light, humidity and air temperature. This results in accurate detection in outdoor environments. Many sensors can also be configured to detect objects up to a specified distance, ignoring objects beyond the set point, resulting in higher accuracy. Furthermore, while inductive and capacitive sensors can detect only moving targets, radar sensors can detect vehicles that are both stationary and in motion.

Optical Sensor (Infrared)

Compared to other technologies, optical sensors are not used as frequently for vehicle detection, but they can be a good option for some applications. An opposed mode optical sensor uses the interruption of a light beam between an emitter and a receiver to detect objects. For example, the presence of a vehicle passing between the emitter and the receiver breaks the beam of light. This technology can be used to detect whether a vehicle has completely exited a car wash.

Measuring Light Grid

Measuring light grids are often used for vehicle detection to start and stop a transaction (e.g., paying a toll at a tollbooth). A sender and a receiver are installed on either side of a toll lane, stretching an array of light beams across the lane. When a vehicle enters the detection area, data from each beam can be used to determine vehicle class and the number of axles with a high level of accuracy.